Safety system for a projectile fuse

Abstract

A fuse includes a detonator-carrying rotor which can be turned from an armed position to a safety position. A first safety mechanism is provided for preventing return of the rotor to the armed position until the projectile has been fired. An additional safety mechanism is provided which prevents the first safety mechanism from releasing the rotor until the additional safety mechanism is deactuated. The additional safety mechanism includes independently operable elements, one of which shifts from a safety position and the other of which shifts into a safety position, in response to acceleration in one direction.

What is claimed is: 
     
       1. A fuse for detonating a projectile, said fuse being of the type comprising a rotatable rotor; a detonator carried by said rotor, said rotor and detonator being rotatable to displace said detonator from a firing position; power storing means energized in response to such displacement of said detonator to urge said rotor and detonator back toward the firing position; restraining means for controlling the rate of return of said detonator to the firing position, said restraining means comprising an armature wheel connected to said rotor, and a swinging arm connected to said armature wheel for regulating the rotation of said armature wheel to regulate the rate of rotation of said rotor; a safety mechanism comprising first and second pins arranged parallel to one another, axially compressed power storing elements urging said pins to a safety position in which one of said pins prevents rotation of said restraining mechanism; said pins being axially displaceable in response to firing of said projectile to release said restraining mechanism; and a locking ball disposed between said pins for being shifted into axial alignment with said one pin by the other pin to prevent return of said one pin to a safety position; the improvement comprising: an additional safety mechanism which functions independently of said first-named safety mechanism, said additional safety mechanism comprising: a plurality of safety pins displaceable independently of one another in response to acceleration forces such that one safety pin tends to release said rotor for rotation and the other tends to restrain said rotor from until acceleration diminishes;   spring means for resisting such displacement of said safety pins; and   means connecting said additional safety mechanism and said first-named safety mechanism such that one of said safety mechanisms is actuable in response to acceleration forces to release said rotor only following displacement of the other of said safety mechanisms by the acceleration forces.     
     
     
       2. A fuse according to claim 1, wherein said second pin of said additional safety mechanism is mounted at the end of a leaf spring whose other end is fixed, said second pin being displaceable into a bore of said rotor in response to acceleration forces to prevent rotation thereof. 
     
     
       3. A fuse according to claim 1, wherein said connecting means is connected between said one pin of said first-named safety mechanism and with a first safety pin of said additional safety mechanism which tends to release said rotor in response to acceleration forces. 
     
     
       4. A fuse according to claim 3, wherein said connecting means comprises a plate having first and second bores, said first pin of said first-named safety mechanism disposed in said first bore and said first safety pin of said additional safety mechanism disposed in said second bore, said plate preventing axial displacement of one of said first pins until the other has been displaced with said one of said first pins then being displaced and simultaneously shifting said plate to prevent return of said other of said first pins to a safety position. 
     
     
       5. A fuse according to claim 4, wherein said other first pin comprising a first portion and a second portion of smaller diameter such that said plate is operable to be shifted into the path of said first portion to prevent return of said other first pin to a safety position; said other first pin being axially displaceable against a compression spring; said first portion, in its safety position, abutting against a projection of said rotor to prevent rotation thereof. 
     
     
       6. A fuse according to claim 4, wherein said one first pin includes a groove which is engaged by said plate to prevent displacement thereof until said other first pin is displaced, said groove including a tapered wall which engages said plate when said one first pin is displaced and cams said plate to a position blocking return of said other first pin to a safety position.